An amoeba with a nasty appetite for human cells is currently being studied by scientists. The amoeba nibbles on human cells in a similar manner to how piranha devour their prey.
( Katherine Ralston )

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Scientists are currently studying a human cell eating bacteria with a nasty appetite. Like a piranha, these diminutive cell killers nibble at human cells destroying them in the process.

The amoeba known as Entamoeba histolytica has been observed biting chunks out of human cells, a type of feeding behavior never before seen in amoeba. The parasite ingested the cellular chunks and gouged out of its prey. Scientists previously thought that the amoeba kill by engulfing their target cells. Another theory suggested that the amoeba poisoned human cells before ingesting them. However, new data indicates that the parasite actually takes little bites off of human cells eventually killing them.

Entamoeba histolytica begins feasting on human cells by taking small bites out of the cell membrane of its prey. After ingesting a large enough amount of the cell membrane material, the membrane collapses and the target cell dies. The amoeba then moves on to its next meal.

"This is the first demonstration that nibbling can serve as a way to kill other cells," said Katherine S. Ralston, a researcher from the UVA. "The findings suggest that amoebae might invade and destroy host intestinal tissue by nibbling alive the cells that line the gut. Intriguingly, there are hints that organisms can also nibble. Perhaps this process is more common than we realize, and it is taken to the extreme in the case of the amoebae, which use nibbling to kill."

Entamoeba histolytica is known to cause a type of diarrhea that has been known to kill humans in developing countries. Due to the potential lethality of the parasite, scientists are currently gathering more data about the amoeba in order to develop more effective treatments in the future. The parasite is known to inhabit the colon where they start preying on human cells. Some of the side-effects caused by the amoeba colonization include colon inflammation, bower diseases and diarrhea. However, there are some cases where no obvious symptoms can be observed.

Researchers studying the amoeba have found that more than 30 percent of infants in a slum neighborhood in Bangladesh have been affected by the parasite within a year after being born. The alarming numbers are a growing cause for concern and both scientists and medical professionals alike are investigating possible treatments. The researchers published their findings in the online journal Nature.

"It has been 111 years exactly since this parasite was named 'histolytica' for its ability to lyse tissues. Finally, the way it kills has been discovered," said chief of UVA Division of Infectious Diseases and International Health Dr. William A. Petri Jr. "This provides an avenue to explore how best to prevent and treat this parasite that infects up to one of every three children by their first birthday in Bangladesh."